#include <bits/stdc++.h>

using namespace std;

#define     mp              make_pair
#define     fs              first
#define     sc              second
#define     pob             pop_back
#define     pub             push_back
#define     eps             1E-7
#define     sz(a)           a.size()
#define     count_one       __builtin_popcount;
#define     count_onell     __builtin_popcountll;
#define     fastIO          ios_base::sync_with_stdio(false)
#define     PI              (acos(-1.0))
#define     linf            (1LL<<62)//>4e18
#define     inf             (0x7f7f7f7f)//>2e9

#ifndef ONLINE_JUDGE
ifstream fin("biconex.in");
ofstream fout("biconex.out");
#endif

const int MAXN = 100010;

int n, m;
int rnk[MAXN], low[MAXN];
vector<int> vec[MAXN];
vector<vector<int> > comp;
stack<pair<int, int> > stk;

void newComp(int tx, int ty) {
    vector<int> c;
    int x, y;
    do {
        x = stk.top().fs; y = stk.top().sc;
        stk.pop();
        c.pub(x); c.pub(y);
    } while(tx != x || ty != y);
    comp.pub(c);
}

void df(int nod, int fn, int val) {
    rnk[nod] = low[nod] = val;
    for(auto it : vec[nod]) if(it != fn) {
        if(!rnk[it]) {
            stk.push(mp(nod, it));
            df(it, nod, val + 1);
            low[nod] = min(low[nod], low[it]);
            if(rnk[nod] <= low[it])
                newComp(nod, it);
        } else
            low[nod] = min(low[nod], rnk[it]);
    }
}

void read() {
	int x, y;

	fin >> n >> m;
	while(m--) {
	    fin >> x >> y;
	    vec[x].pub(y);
	    vec[y].pub(x);
	}
}

int main() {
	read();
    df(1, 0, 1);
    fout << comp.size() << "\n";
    for(auto it : comp) {
        sort(it.begin(), it.end());
        it.resize(distance(it.begin(), unique(it.begin(), it.end())));
        for(auto jt : it)
            fout << jt << " ";
        fout << "\n";
    }
    return 0;
}